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Flying Weight Extra 300? - 1/27/2013 10:06 PM   
bbbair


 

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From: Belleville, ON, CANADA
Status: offline 		OK Guys;

I have acquired an older Goldberg Extra 300 (90 size) that was built from a kit (kit #K55) it looks good and I have flown it BUT it flew like a brick.

I finally checked the weight and found that it came in at about 10.5 pounds... the listed Flying weight on the instructions is 7.5 to 8.5 pounds! http://www.carlgoldbergproducts.com/discontinued/gbga0055.html

No wonder it flew poorly!

So for the passed year I have been shaving off corners and replaced the wheels, landing gear, engine, cutting back the cowl - all the things that I could think of to reduce the weight of this plane... and it is still too heavy... 9lbs 10 oz. with the cowl removed

The wing alone is 2 lbs 6 oz (foam core)
The Fuse alone is 7 lbs 4 oz

So now I am left to look for ways to cut off a pound and a half from this plane... BUT !

Before I go too crazy - I thought that I'd ask the RCU if this is a normal weight or if the builder just managed to add too much wood/glue or something??

My point and question; Was this a poorly designed plane (too heavy) or was the extra weight a matter of the builder doing something wrong?

So let's throw it out there for discussion!

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RE: Flying Weight Extra 300? - 1/27/2013 10:18 PM   
karolh


 

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Status: offline 		First off the CG Extra 300 is one of the nicest and well behaved flying sport models bar non that I have flown, and to the best of my knowledge it was never supplied with a foam wing, but had built up one piece wing that was quite light. Rather than start answering your questions here and repeating myself do a search in this forum for "Goldberg Extra 300", as there is a lenghty thread on the CG Extra 300 which answers all of your questions and then some. CG Extra's have been known to weigh in excess of 11 lbs. and still fly great, as mine at 10 lbs flat with a G23 gas engine is simply a dream to fly.

Karol

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RE: Flying Weight Extra 300? - 1/27/2013 10:19 PM   
eddieC



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Status: offline 		What engine does it have? 

That's quite a bit overweight. 


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RE: Flying Weight Extra 300? - 1/27/2013 10:26 PM   
OldScaleGuy



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Status: offline 		I agree with Karol. The weight is not extreme, it is heavy but not to the point where it shouldn't fly well. I have built 2 of these and again agree with Karol that they are an absolute joy to fly. Something else is going on with your plane. How about CG, it is too nose heavy? Just kickin' tires. Are you sure it is a Goldberg? The Goldberg design was a built up wing. I have heard of guys increasing the wing size and/or changing to a foam wing. If the wing is foam, who knows,, the builder may have changed the airfoil making it an altogether different type of flyer.

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RE: Flying Weight Extra 300? - 1/27/2013 10:26 PM   
bbbair


 

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Status: offline 		The First Engine was a Saito 120.
The Current Engine is a DLE 20cc.

I considered a smaller engine - but I don't think it would work...

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RE: Flying Weight Extra 300? - 1/27/2013 10:32 PM   
eddieC



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Status: offline 		Engine sounds ok. It must be the foam wing. That would change it a lot - the airfoil, not so much with weight but the flying characteristics.

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RE: Flying Weight Extra 300? - 1/27/2013 10:34 PM   
OldScaleGuy



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Status: offline 		Either will do a good job. My first one went from an O.S. 120 four stoke to a Saito 150, the second one has an O.S. 1.08. The point being you are in the right engine size range. What is the wing span?
Eddie, this is a good one I might not be very good, but I am fun to watch!
My old saying is "i am not very good but i sure am slow"

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RE: Flying Weight Extra 300? - 1/27/2013 11:31 PM   
eddieC



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Status: offline 		OSG,
Thanx! I used to tell my old boss: 'I got two speeds: this one and full stop. Which do you want?'  Lol. 

I'm thinking the C of G and airfoil are the culprits here. Sounds like a different wing was substituted. 



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RE: Flying Weight Extra 300? - 1/27/2013 11:59 PM   
Gray Beard


 

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Status: offline 		First do what Karol said and look up the thread, there are about 60 pages to it. Second, it isn't a 90 size if it is the CG Extra, they called it a 60 size and it should have a 68 inch built up wing. I can't recall how many I have built, it is more then 6 and under 8? I haven't had mine on a scale in a while but I think it is at about 11 pounds with a YS 120 and all FGS glass parts? I could be wrong about that but when I say the CG Extra is the best of the Extras I have ever flown in any size is something I'm sure of. I have used all glow engines in them though, usually 120 four strokes either OS or YS. The best one I built used the YS 140 Sport engine. The problem you are having may be the air foil itself? It isn't the weight of the plane. They are heavy for there size but most of the weight is from the engine. In my case it is the odd ball landing gear I have on it too but it is the best flying plane I have and I'm not making any changes to it.
All answers to any questions you have should be in the thread plus photos of the plane so you can make sure it is the CG Extra you have.

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RE: Flying Weight Extra 300? - 1/28/2013 3:03 PM   
karolh


 

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Status: offline 		bbbair,

Maybe someone can assist by posting a link to the Goldberg Extra 300 thread for you , if I knew how to I would.

Karol

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RE: Flying Weight Extra 300? - 1/28/2013 3:25 PM   
OldScaleGuy



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Status: offline 		Here you go:
http://www.rcuniverse.com/forum/m_2403807/tm.htm

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RE: Flying Weight Extra 300? - 1/28/2013 3:58 PM   
bbbair


 

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Status: offline 		Thanks Guys!

I went through that thread and it became clear in a hurry that there are a lot of 10 pound Extras out there that fly just fine - I was just reading the instructions and looking at my own weights trying to figure out what went wrong...

So I guess the thing to do is clean it up and wait for spring because this is as good as it is going to get!

The DLE 20 develops 2.5 hp so the Extra will fly - I just have to be careful on my landings... details to follow.

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RE: Flying Weight Extra 300? - 1/28/2013 7:07 PM   
Gray Beard


 

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Status: offline 		If it is the CG Extra you have you may want to get the templates and plans then build the stock wing for your plane. Not sure what you would think of as poor flying but I have never flown one that wasn't perfect but they have all been stock built or just minor mods. I have never seen one with a foam core wing so I suspect there is the problem or perhaps the incidence or CG? Hard to say. If we were only allowed one plane this would be the one I kept. It's even smoother then the 40% I had and a ton better then the 30% I was flying. You can build the Great Planes Extra kit and make it a bunch lighter, it's another good one.

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RE: Flying Weight Extra 300? - 1/29/2013 11:12 PM   
karolh


 

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Status: offline 		How about sending us a picture of your model.

Karol

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RE: Flying Weight Extra 300? - 1/30/2013 12:52 AM   
Jollidude



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From: Dartmouth, NS, CANADA
Status: offline 		Mine weighs 9 1/2 lbs and flys great. Fiberglass cowl and wheel pants, OS 91FX for power, flys it with authority.

Cheers!

Jollidude

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